A person who tries extremely hard during practice. This teammate will exert all of their energy by sprinting, to "one up" someone else to lead the group. This will happen at appropiate and inappropitate times. When somebody takes part in this act, the other teammates tend to get aggravated. When a person is a speed demon during practices. Doesn't necessarily mean he or she is the best or fastest in the team; just means they practices intensely. This word is used in a neggative way.